Effects of hydroxyproline and vitamin B-6 on oxalate synthesis in rats.
Relationships among dietary hydroxyproline (HP), vitamin B-6 and endogenous oxalate formation have been studied. In the absence of HP, urinary oxalate excretion was greatest among rats fed vitamin B-6-deficient diets. Supplementation of rat diets with 5.2% HP markedly increased the oxalate excretion of rats fed 0, 0.2 or 10 mg of vitamin B-6 per 100 g of diet, the increases being 2-, 19- and 15-fold respectively. The metabolism of several 14C-labeled oxalate precursors was altered in vitamin B-6-deficient rats. The feeding of HP and different levels of vitamin B-6 also altered their metabolism. The feeding of HP to vitamin B-6-deficient rats resulted in a decrease in the amount of 14C-oxalate formed from injected 14C-labeled glycine, glycolate or glyoxylate. In contrast, HP feeding to rats given 0.2 mg of vitamin B-6 per 100 g, resulted in a marked increase in oxalate formation from injected 14C-glycolate, as well as a decrease in respiratory 14CO2 from injected 14C-labeled glycolate and glyoxylate. HP feedings did not significantly alter the metabolism of these two injected compounds to oxalate or CO2 among rats fed the higher level of vitamin B-6, although some elevation of oxalate formation from glycolate was noted. HP feeding reduced the growth rates of all the rats, but growth depression was greatest in the vitamin B-6-deficient group.
D000818:Animals; D001835:Body Weight / Q000187:drug effects; D002245:Carbon Dioxide; D004032:Diet; D005998:Glycine / Q000378:metabolism; D006016:Glycolates / Q000378:metabolism; D006038:Glyoxylates / Q000378:metabolism; D006909:Hydroxyproline / Q000494:pharmacology*; D008297:Male; D010070:Oxalates / Q000096:biosynthesis* / Q000652:urine; D011736:Pyridoxine / Q000494:pharmacology*; D051381:Rats; D026681:Vitamin B 6 Deficiency / Q000378:metabolism
D006016:Glycolates; D006038:Glyoxylates; D010070:Oxalates; C031149:glycolic acid; D002245:Carbon Dioxide; C031150:glyoxylic acid; D011736:Pyridoxine; D006909:Hydroxyproline; D005998:Glycine